Embodiments of the invention generally relate to plasma actuation, and more particularly to tip-vortex mitigation and wake mitigation via plasma actuation for reduction of interaction events.
Generally, tip vortices and wakes shed by blades in aircraft engines, power generation equipment (e.g., wind and gas turbines), and their interactions with other systems utilizing airfoils are a source of aerodynamic loss, noise, and excitation phenomena.
For example, tip-vortices and wake from fan blades interact with downstream stators to give rise to fan noise, which is one of the main sources of aircraft engine noise. This may be exacerbated in fan designs such as un-ducted fans which feature two-prop fans within relatively close proximity. The interaction noise in such designs becomes a technological hurdle for the design's success. Furthermore, interaction events give rise to aerodynamic issues, for example in turbo-machinery, where unsteady impulses due to the interaction events may excite a structural response and lead to structural issues. Tip vortices further give rise to noise problems where self-noise is an important issue, for example as in wind turbines.
Traditional approaches to wake mitigation (i.e., the removal of the wake velocity deficit that causes the unsteady aerodynamic interaction) have relied from blowing at the trailing edge of high-momentum fluid, or blowing schemes with steady and unsteady injection to rapidly mix out the wake to lower the momentum requirements. All of these however need sources of high momentum fluid that require power, but more importantly, have a high system cost due to the plumbing needs of routing high-pressure fluids through complex mechanical systems (e.g., rotating fan blades). As such, wake mitigation with actuators that have low-power requirements, and are easier to integrate into complex systems is a promising technological alternative.
Thus, example embodiments are provided which provide a reduction in interaction events without the limitations of the conventional art.